I need the arduino to do some polling and send the data out via ethernet, is this possible with the ethernet microcontroller? (Im wondering this because getting the ethernet microcontroller would help save on physical space).

I have not used the Arduino Ethernet. It does not have a usb port built in, so take that into consideration. If you want that function, you will need a usb card.

The advantage of the ethernet shield is the ability to move it from device to device. If you find the Uno does not have the memory or digital pin capability you require, you can purchase a Mega2560 (like I did), and move the shield to it.

Either will do. I have a Uno with built-in Ethernet and a mega with separate shield. I believe both can use POE, I have never felt the need to use it with either.

(edit)I'm amazed at what Tim wrote, and the price. If you want to go that way, I suspect you would be better off with an Etherten like mine. It has USB, Ethernet and SD card all-in-one and seems competitively priced. I guess an Arduino with no USB has a place in this world, but surely not for a school project.

The Etherten looks pretty ideal for me actually, im just wondering about the coding, does the Etherten use the same code that the Arduinos use? If it doesnt i would stick with the Arduino because of the large library of existing programs and codes available.

So im assuming it can be be programmed through USB to poll data and send this data out via ethernet? I want to be 100% sure before ordering, because im on a limited schedule and want to avoid having to avoid another product if it doesnt meet my needs.

The EtherTen is just a tarted-up Uno and uses the standard Arduino IDE in exactly the same way - including all the libraries.. It requires its own driver for initial installation, as it is a unique third-party device.

You use the desktop to programme it via USB cable. The devices you are polling are usually connected separately by various means to the sockets provided.

The data is sent from the Ethernet and that is sent direct to the world. I use the cosm feed service for this, i.e. people go to cosm, not to me, and I guess it is the obvious approach for your project.

Ah... I misunderstood you. What you are proposing is a hell of a lot simpler and I'm sure you will be fine. You might find this interesting http://www.parallax.com/tabid/393/default.aspxIt is not for Arduino but can be painlessly adapted, and is just the thing for you get the leading edge, and piss over all your colleagues........